Combination lock apparatus and slip coupling therefor



Sept. 27, 1966 P. J. ETHINGTON COMBINATION LOCK APPARATUS AND SLIP COUPLING THEREFOR Filed Sept. 26, 1963 INVENTOR. P401. J ETH/A/GTQ/L/ BY W WW United States Patent 3,274,811 1 COMBINATION LOCK APPARATUS AND SLIP CGUPLING THEREFOR Paul J. Ethington, 1418 Washington Blvd., Birmingham, Mich. Filed Sept. 26, 1963, Ser. No. 311,860 9 Claims. (Cl. '70-301) This invention relates generally to combination locks, and more particularly to improved combination lock apparatus incorporating a slip coupling.

Many combination locks are made with a plurality of rotatable code elements or tumblers each of which has a notch in its periphery. The shackle, or any equivalent lock release member, is retained in a locking position by a pivoted dog, which is prevented from moving to a position in which the release member can be moved to open position by the code elements, when in their blocking positions, until all of the code element notches are aligned and the code elements positioned in unblocking positions such that the dog can be moved. These combination locks require non-rotatable spacers between the code elements and a spring for causing frictional engagement between the spacers and the code elements to maintain the code elements in a given rotative position. Conventionally, the combination is dialed by rotating the code elements in sequence to their unblocking positions. In many combination locks, the combination can be felt, when it is not known, by feeling when the notch in each code element is positioned in a predetermined position with respect to the pivoted dog. Thus, such locks are susceptible to being opened by unauthorized personnel.

It is an object of this invention, therefore, to provide combination lock apparatus which is feel proof, is easily assembled, is made from a reduced number of parts, and which is simple and economical to manufacture. This is accomplished by using a new procedure in aligning the notches of the code elements in an unblocking position in which the lock member is released. First, two of the code elements are rotated relatively until the notches are aligned with each other in a blocking position, then the two code elements are rotated in unison to locate the notches in the unblocking positions, and finally the third code element is rotated independently to locate its notch in the unblocking position. In particular, this is provided by a slip coupling assembly comprising the two code elements which can be preassembled to facilitate complete assembly of the lock apparatus.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims, and the accompanying drawing in which:

FIGURE 1 is a sectional view of the combination lock apparatus of this invention;

FIGURE 2 is another sectional view of the combination lock apparatus of this invention, looking substantially along the line 22 in FIG. 1; and

FIGURES 3 and 4 are fragmentary detail sectional views of the apparatus of this invention, looking substantially along the lines 3-3 and 44, respectively, in FIG. 1.

With reference to the drawing, the improved combination lock apparatus of this invention, indicated generally at 10, is illustrated in FIG. 1 as including a housing 12 and a shackle or hasp 14, which is of the conventional generally U shape having a pair of legs 16 and 18. The shackle leg 18 is slidably mounted in a guide plate 20 secured to the housing 12 and an opening 22 formed in the housing wall 24. The shackle leg 16 is formed with a notch 26, adjacent one end, and a dog 28, pivotally supported in the housing on a rivet 30 so that the dog is ice pivotally movable between the solid and broken line positions shown in FIG. 2, has a hook-shape end portion 32 which projects into the notch 26in the solid line position of the dog 28 to prevent movement of the shackle 14 in a direction to withdraw the leg 16 from the housing 12. In the illustrated embodiment of the invention, the housing 12 consists of two flanged sections 34 and 36 which are connected by the rivet 30 and another pair of rivets 38 and 40. A projection 42 on the shackle leg 18 is engageable with the housing wall 24 to prevent complete withdrawal of the leg 18 from the housing 12 when the shackle 14 is moved to its release position in which leg 16 is moved out of the housing 12. The projection 42 is also engageable with plate 20 to define the locking position of shackle 14.

The housing section 34 has a dial plate 44 secured to the outer face thereof by the rivets 30, 38 and 40, and the dial plate 44 is provided with the usual scale of numbers (not shown) arranged adjacent its periphery. A dial knob 46, having a pointer 48 formed thereon, has an axially projecting hub 50 which is rotatably supported in an opening 52 in the housing section 34 positioned so that it is concentric with the dial plate 44. A first code element or tumbler 54, secured to the inner end of the hub 50 at a position within the housing 12, maintains the dial knob 46 in a supported position on the housing section 34. As shown in FIG. 4, the code element 54 is of generally plate or disc shape and has a notch 56 formed in the peripheral thereof and a drive pin or member 58 which projects from one face of the element 54 in a direction away from the dial plate 44. The pin or projection 58 is readily formed by punching the opposite face of the element 54 so that metal projects from the one face of the element to form the pin 58.

A shaft 60 is secured to a substantially central portion of the housing section 36 so that it is axially aligned with the hub 50 and projects into an axial cavity 62 in the hub 50. The shaft 60 has an enlarged diameter portion 64 which abuts the inner surface of the housing section 36, and a head 66 is formed on the outer end of the shaft 60 so as to firmly mount the shaft 60 on the housing section 36. A stop pin 68 is also secured to the housing section 36 at a position adjacent the shaft 60 so that the pin 68 projects into the housing 12.

A slip coupling 70 is mounted on the shaft 60 at a position generally between the code element 54 and the stop pin 68. The slip coupling 70 consists of a pair of code elements or tumblers 72 and 74 mounted on a supporting and retaining element 76 which constitutes a clutch means. The code element or tumbler 72 is substantially identical to the code element 54 in that it is of generally plate or disc shape, having a pair of opposed flat faces 78 and 80, and a notch 82 formed in the periphery thereof of a shape corresponding to the shape of the notch 56. The element 72 also has a pin 84, sometimes referred to as a stop pin, projecting from the face thereof and positioned on a radius such that it is engageable with a side surface of the stop pin 68 as shown in FIG. 2. The face 80 is spaced from the end of stop pin 68.

The code element or tumbler 74 is substantially identical to the elements 54 and 72, having opposed flat faces 86 and 88, and a peripheral notch 90 of the same shape as the notches 56 and 82. The code element 74 also has a pin 92, sometimes referred to as a drive pin, projecting from the face 88 thereof and disposed on a radius which is the same as the radius on which pin 58 is located. The

element 74 is of a diameter slightly larger than the di' ameters of the elements 54 and 72. In the assembly of the slip coupling 70, the code elements 72 and 74 are positioned in face-to-face engagement so that the faces 78 and 86, respectively, thereof are engaged and the pins 84 and 92 project in opposite directions from the coupling 70, and

so that axial openings 94 in the code elements are aligned. The support element 76, which is of generally tubular shape, is then inserted through the openings 94 and flanges 96 and 97 on the ends of the supporting element 76 engage, respectively, the faces 88 of the code element 74, and face 80 of element 72. The element 76 is of a diameter such that it frictionally engages the inner or bearing surfaces of the code elements 72 and 74 with sufiicient force to enable rotation of element 76 by rotation of either code element without slippage. However, this frictional engagement is not so tight that the element-s 72 and 74 cannot be rotated about the element 76 when forces are applied to the pins 84 and 92 in directions such that oppositely directed torques are applied to the code elements. The engagement is sufliciently tight that an external force is necessary in order to rotate either of the code elements 72 or 74 about the element 76.

The supporting element 76 is inserted on the shaft 60 to a position in which the flanged end 98 of the element 76 engages the enlarged shaft portion 64. In this position of the slip coupling 70, the pin 84 on the code element 72 is engageable with the stop pin 68 and the pin 92 on the code element 74 is engageable with the pin 58 on the code element 54.

The frictional loadings on the various components of the lock apparatus have the following relationships, the purposes of which will be apparent during explanation of the operation of apparatus 10:

(1) The supporting element 76 is tight enough on shaft 60 so that it will hold its position during dialing and during vibration or handling when apparatus 10 is left unlocked. The torque required to rotate element 76 on shaft 60 is, therefore, relatively low and is referred to as rotational torque.

(2) The slip torque, namely, the torque required to rotate a code element 72 or 74 relative to element 76, must be higher than the rotational torque.

(3) The knob torque, namely, the torque required to rotate hub 50 on casing 12 may be any arbitrary value provided it will hold knob 46 against accidental movement. It is desirably much higher than either rotational torque or slip torque so that additional torque imposed during dialing is not perceptible to the operator.

In the assembly of the apparatus 10, the slip coupling is assembled on the shaft 60 and the dial knob 46 is mounted on the housing section 34. The housing sections 34 and 36 are then positioned face to face as shown in FIG. 1 and the rivets 30, 38 and 40 are installed to connect the housing sections and to pivotally support the dog 28. As shown in FIG. 2, the dog 28 has a projection 100 formed intermediate its ends which is of a sizeto fit in the notches 56, 82 and 90 formed in the code elements. The projection 100 is of a thickness at least equal to the distance between the outer face 80 of the code element 72 and the opposite face of code element 54. In other Words, the thickness of dog 28 is equal to the combined thicknesses of the code elements. Consequently, the projection 100 is blocked by the peripheries of any one or all of the code elements 54, 72 and 74 if a pulling force is exerted on shackle 14 so as to urge dog 28 toward its broken line position. When all of the notches 56, 82 and 90 are aligned, the projection 100 is movable into the aligned notches so that the dog 28 is movable to its broken line position shown in FIG. 2. In this position, the dog 28 is out of the path of the shackle leg 16 during withdrawal of the leg 16 from the housing 12. Consequently, when the combination for the particular lock apparatus 10 is dialed, all of the notches 56, 82 and 90 are in a position such that the dog 28 is movable to its broken line position, as illustrated in FIG. 2. The combination is dialed by first rotating the knob 46 in one direction until the pin 58 engages the pin 92 so as to rotate the slip coupling 70 as a unit on the shaft 60. The slip coupling 70 will rotate as a unit until the pin 84 engages the stop pin 68. At such time, rotation of the code element 72 is restrained so that .4 further turning of the knob 46 causes relative rotation of the code elements 72 and 74 with a slippage of one or both of the code elements 72 and 74 on the supporting element 76. The pins 58, 92, 84 and 68 are located so that when the first number in the combination is dialed, the notches 82 and '90 in the code elements 72 and 74 are aligned.

The knob 46 isthen rotated in an opposite direction so that the pin 58 will engage the opposite side of the pin 92 and rotate the slip coupling 70, as a unit, in an opposite direction. When the second number in the combination is reached, the code element notches 82 and are positioned as shown in FIG. 2 so that the dog projection can be moved into the notches. The dial knob 46 is then rotated in an opposite direction until the pointer 48 indicates the third number in the combination at which time the notch 56 in the code element 54 is aligned with the notches 82 and 90. The shackle 14 can then be moved in a direction to withdraw the leg 16 from the housing 12. During such withdrawal, the hook-shape end portion 32 of the dog 28 rides on the shackle notch 26 so that the dog 28 is moved in a counterclockwise direction, as viewed in FIG. 2, to move the dog projection 100 into the aligned notches 56, 82 and 90. When the shackle 14 has been manipulated so that the leg 16 has been reinserted into the housing 12 to a position defined by engagement of the projection 42 with the plate 20, as shown in FIG. 2, the shackle 14 is readily locked in this position by merely twirling the dial knob 46 to move the code elements 54, 72 and 74. Such movement moves the notches 56, 82 and 90 out of alignment so that one or more of the code elements will block movement of the dog 28 toward its broken line position.

The code element 74 is of a larger diameter to prevent the application of a restraining torque on code element 72 by dog 28 in the event shackle 14 is pulled during dialing. Since element 72 is rotated at times only by the friction between it and element 76, a restraining torque on element 72 by dog 28 at such a time in excess of slip torque would cause undesirable rotation of element 72. This is prevented by making positively driven element 74 of a larger diameter such that any restraining torque applied by dog 28 can only be applied to element 74.

From the above description it is seen that this invention provides combination lock apparatus 10 which includes a slip coupling 70 that can be preassembled, manufactured in quantity, and supplied for later assembly with com bination locks of the type embodying code elements. The element 76 in coupling 70 is preferably formed from a plastic material having low friction characteristics, such as polyethylene or nylon. A large number of different lock combinations are readily attained by varying the location of the pins 84 and 92 with respect to the notches 56, 82 and 90, respectively. A lock apparatus 10 utilizing a slip coupling 70 does not require springs and spacers between the code elements which add to the cost of raw material and assembly. Furthermore, since the first number in the combination accomplishes the alignment of the notches in the code elements in the slip coupling, the lock -appara-- tus 10 is feel proof since it is not possible for a person manipulating the dial knob 46 to detect this alignment. Although the supporting element 76 in the slip coupling 70 is illustrated as having flanges at both ends, to increase the friction between elements 72 and 74 flanges 96 may be eliminated if this increased friction is not needed. Also, in the event the lock apparatus 10 is constructed so that openings, as shown in applicants copending application entitled Combination Lock Apparatus filed on even date herewith and identified as Serial No. 311,859, or inner periphery notches, rather than the outer periphery notches illustrated in the drawing, are aligned in the code elements to define the unlocking position of the code elements, the supporting element 76 may be mounted on the radial-1y outer sides or edges of the code elements 72 and 74 rather than on the radially inner sides or edges as shown. The above modifications do not affect the essential characteristic of the element 76, namely, to connect the code element 72 and 74 so that they are r0- tatable together as a unit until oppositely directed torques are applied to the code elements 72 and 74 at which time they are rotatable relative to each other in opposite directions without affecting their subsequent movement as a unit with the supporting element 76.

It will be understood that the combination lock apparatus and slip coupling therefor which are herein disclosed and described are presented for purposes of explanation and illustration and are not intended to indicate limits of the invention, the scope of which is defined by the following claims.

What is claimed is:

1. A slip coupling comprising a pair of combination lock code elements each of which .is of a substantially disc shape having a pair of opposite faces and a code pin projecting from one of said faces, said code elements being arranged in face-to-face engagement so that the pins thereon project in opposite directions therefrom, and a support and retainer element arranged in a supporting relation with said code elements for rotatable movement therewith as a unit, said code elements being supported on said retainer element so that the code elements are rotatable with respect to each other in response to the application of forces to .the pins thereon directed so that oppositely directed torques are applied to said code elements.

2. A slip coupling comprising a pair of combination lock code elements each of which is of a substantially flat disc shape having at least one generally circular edge and a pair of opposite faces and a code pin projecting from one of said faces, said code elements being arranged in face-to-face engagement so that the pins thereon project in opposite directions therefrom, and a support and retainer element frictionally engaged with said one edge of each code element so as to be in a supporting relation with said code elements for rotatable movement therewith as a unit, said code elements being supported on said retainer element so that the code elements are rotatable with respect to each other in response to the application of forces to the pins thereon directed so that oppositely directed torques are applied to said code elements.

3. A slip coupling Comprising a generally tubular support and retainer element formed of a plastic material having low friction characeristics, a pair of code elements rotatably supported on said retainer element, each of said code elements being of a generally flat shape having opposite faces and a pin extending from one of said faces, said code elements being supported on said retainer element so that they are in face-to-face engagement and have the pins thereon projecting in opposite directions therefrom, means engageable with one of said pins for rotating said elements, and means engageable with the other one of said pins for restraining rotation of the code element having said other pin to provide for relative rotation of said code elements.

4. A slip coupling comprising a generally tubular support and retainer element formed of a plastic material having low frictional characteristics, means rotatably supporting said retainer element, a pair of annular code elements rotatably supported in a coaxial relation on said retainer element so that said retainer element extends through said code elements, each of said code elements being of a generally fiat shape having opposite faces and a pin extending from one of said faces, a notch in the periphery of each code element, said code elements being supported on said retainer element so that they are in face-to-face engagement and have the pins thereon projecting in opposite directions therefrom, means engageable with one of said pins fior rotating said elements as a unit, and means engageable with the other one of said pins for restraining rotation of the code element having said other pin to provide for relative rotation of said code elements to positions in which the notches therein are aligned.

5. Combination lock apparatus comprising a housing, a slip coupling comprising a substantially tubular support and retainer element rotatably supported in said housing, a pair of code elements each of which is of a generally disc shape having a pair of opposite flat faces and a pin projecting from one of said faces, said code elements being arranged in a face-to-face engagement so that the pins thereon project in opposite directions there from, said code elements being mounted in a coaxial arrangement on said retainer element and being frictiontally retained thereon so that said slip coupling is rotatable :as a unit, alignable openings in said code elements, a stop pin on said housing engageable with one of said slip coupling pins, a dial knob rotatably mounted on said housing, a third code element mounted on said dial knob for rotation therewith, said third code element having a drive pin thereon engageable with the other pin in said slip coupling so that on rotation of said dial knob with said drive pin in engagement with said other coupling pin, said coupling is rotatable as a unit to a position in which said one coupling pin engages said stop pin whereby on further rotation of said dial knob, said slip coupling code elements rotate with respect to each other with one or the other code element in said coupling slipping on said retainer element to a position in which the openings in said code elements are aligned.

6. Combination lock apparatus comprising a housing, a locking dog pivotally mounted in said housing, a shaft in said housing, a slip coupling comprising a substantially tubular support and retainer element rotatably supported on said shaft, a pair of code elements each of which is of a generally annular disc shape having a pair of opposite flat faces and a pin projecting from one of said faces, said code elements being arranged in a faceto-face engagement so that the pins thereon project in opposite directions therefrom, said code elements being mounted in a coaxial arrangement on said retainer element and being frictionally retained thereon so that said slip coupling is rotatable as a unit on said shaft, a stop pin on said housing engageable with one of said slip coupling pins, a dial knob rotatably mounted on said housing, a third code element mounted on said dial knob for rotation therewith, a notch in the periphery of each of said code elements, said third code element having a drive pin thereon engageable with the other drive pin in said slip coupling so that on rotation of said dia'l knob with said drive pin in engagement with said other coupling pin, said coupling is rotatable as a unit to a position in which said one coupling pin engages said stop pin whereby on further rotation of said dial knob, said slip coupling code elements rotate with respect to each other with one or the other code element in said coupling slipping on said retainer element to a position in which the notches in said coupling code elements are aligned, said knob :being rotatable to align the notch in said third code element with the aligned notches in said coupling code elements, said dog being movable to an unlocking position in which it projects into said aligned notches.

7. For use in combination locks, a pair of annular plates each having one peripheral edge defining a notch and the other peripheral edge defining a circular bearing surface for rotational support of said plates, a resilient clutch sleeve in engagement with the circular bearing surface and exerting a radially directed force thereagainst by reason of its resilience thereby frictionally coupling the plates together, said clutch sleeve and bearing surface being adapted to slip at a predetermined value of torque, a stop member on one plate and a driving member on the other plate whereby the plates may be rotated relatively to align said notches by holding the stop member and applying a torque greater than said value to the driving member and whereby the plates may be rotated together by releasing the stop member "and applying a torque less than said value to the driving member.

'8. For use in combination locks, a pair of annular plates each having one peripheral edge defining a notch and the other peripheral edge defining a circular bearing surface for rotational support of said plates, a resilient clutch sleeve of circular cross section disposed coaxially of the bearing surface, said sleeve having a flange on each end extending over the outer face of the corresponding plate and exerting an axially directed force thereagainst by reason of its resilience to thereby friotionally couple the plates together, said plates being adapted to slip at a predetermined value of torque, a stop member on one plate and a driving member on the other plate whereby the plates may be rotated relatively to align said notches by holding the stop member and applying a torque greater than said value to the driving members and whereby the plates may be rotated together by releasing the stop member and'applying a torque less than said value to the driving member.

9. In combination lock apparatus, three rotatable code elements which are moved to predetermined positions to enable unlocking, clutch means coupling two of said elements together so that said two elements are rotatable as a unit in the absence of oppositely directed torques on said elements and are relatively rotatable on the application of oppositely directed torques thereto, the third one of said elements being releasably drivingly connected to only one of said two elements for first applying a torque to said one element relative to the other one of said two elements to locate said two elements in predetermined relative positions and to subsequently rotate said unit to said predetermined positions for said two elements, said third element being subsequently rotatable independently of said first two elements to said predetermined position therefor.

References Cited by the Examiner UNITED STATES PATENTS 429,092 5/ 1890 Houck 70-302 497,761 5/1893 Brown 70-302 3,038,325 6/1962 Maynard 70443 3,180,119 4/1965 Goldfarb 7063 BOBBY R. GAY, Primary Examiner.

ALBERT H. KAMPE, PATRICK A. CLIFFORD,

Examiners. 

1. A SLIP COUPLING COMPRISING A PAIR OF COMBINATION LOCK CODE ELEMENTS EACH OF WHICH IS OF A SUBSTANTIALLY DISC SHAPED HAVING A PAIR OF OPPOSITE FACES AND A CODE PIN PROJECTING FROM ONE OF SAID FACES, SAID CODE ELEMETS BEING ARRANGED IN FACE-TO-FACE ENGAGEMENT SO THAT THE PINS THEREON PROJECT IN OPPOSITE DIRECTIONS THEREFROM, AND A SUPPORT AND RETAINER ELEMENT ARRANGED IN A SUPPORTING RELATION WITH SAID CODE ELEMENTS FOR ROTATABLE MOVEMENT THEREWITH AS A UNIT, SAID CODE ELEMENTS BEING SUPPORTED ON SAID RETAINER ELEMENT SO THAT THE CODE ELEMENTS ARE ROTATABLE WITH RESPECT TO EACH OTHER IN RESPONSIVE TO THE APPLICATION OF FORCE TO THE PINS THEREON DIRECTION SO THAT OPPOSITELY DIRECTED TORQUE ARE APPLIED TO SAID CODE ELEMENTS. 